Ignition apparatus



March 6, 1962 E, H. WISCHHUSEN 3,024,326

IGNITION APPARATUS Original Filed July 24, 1956 A; n '9 A O INVENTOR.

EGON H. WISCHHUSEN ATTOR YS United rates 3,ii24,326 Patented Mar. 6, 1962 3,ll24,326 KGNETHGN APPARATUS Egon H. Wischhusen, Sidney, N.Y., assignor to The Bendix Corporation, Sidney, N.Y., a corporation of Delaware Original appiication duly 24, 1956, Ser. No. 599,861, now Patent No. 2,978,550, dated Apr. 4, 1961. Divided and this application July 19, 396i), Ser. No. 43,821

2 Claims. (Cl. 20ll3ll) This invention relates to an improved means for attaching a sleeve-like member to a shaft. The attaching means of the invention is particularly useful in, and is shown in a magneto of, an ignition system of an internal combustion engine, although it is obviously not limited to use therein.

This application is a division of application Serial No. 599,861, filed July 24, 1956, now Patent No. 2,978,550.

In the usualprior distributor of an ignition system the cam operating the low tension breaker is connected to the main shaft of the distributor by a key. Such construction, to be satisfactory, requires close tolerances in the machining of the shaft, the cam, and of the key means attaching the cam to the shaft, since unless the cam fits tightly, and is held in accurately angularly oriented position on the shaft, the timing of the discharges from the distributor to the spark plugs will be inaccurate.

There is illustrated herein a distributor which employs the device of the invention for attaching the distributor cam to the shaft of the distributor. The attaching means of the invention is of such construction that a high precision in the machining of the means retaining the cam at the desired angle on the shaft is not necessary, the cam is easily assembled upon or disassembled from the shaft, and the cam attaching means always retains the cam tightly and accurately located in the desired angular position upon the shaft throughout the life of the distributor.

The invention has among its objects the provision of an improved means for attaching a sleeve-like member to a shaft.

Another object of the invention lies in the provision of an improved means for attaching the cam for operating the low tension breaker contacts of a distributor to the main shaft thereof, said attaching means being simple and inexpensive, allowing the ready assembly and disassembly of the cam, and insuring that the cam will at all times be accurately maintained in the desired angular position on the shaft.

The above and further objects of the invention relating to economics of construction and operation of the magneto of the invention will be more readily apparent from consideration of the following specification, and of the accompanying drawings forming a part thereof, which describe and illustrate a preferred embodiment of the distributor.

In the drawings:

FIG. 1 is a fragmentary view on an enlarged scale and generally in longitudinal axial section of the distributor portion of an illustrative embodiment of magneto, certain of the parts being shown in side elevation.

FIG. 2 is a fragmentary view in end elevation of such unit from the cap end of the distributor, a major portion of such cap being broken away to show the low tension breaker assembly of the distributor.

FIG. 3 is an enlarged fragmentary viewin axial cross section through the main shaft of the distributor in the location of the cam mounted on such shaft.

FIG. 4 is an exploded view in perspective of a fragment of the main shaft of the distributor, the cam for operating the low tension breaker assembly of the dis- I cludes a generator 10 contained in the left-hand end (as it is shown in FIG. 1) of body portion 11 of the housing of the unit, and a distributor contained in the righthand end of such unit. A cap 12, attached to the body 11 of the housing by screws 14 covers the distributor.v

Preferably both the housings of the body 11 and of the cap 12 are made of metal such as steel.

The magneto unit has a main longitudinally extending drive shaft 15 adapted to be rotated in synchronism with an internal combustion engine (not shown) to which it is drivingly connected. Shaft 15 carries the rotor of the generator of the magneto, and also has non-rotatably connected thereto a cam 16 for operating a low tension breaker assembly 17 of the distributor. The right-hand end of shaft 15, as it is shown in FIG. 1, extends through journal 19 of the magneto unit and carries an insulating distributor rotor body 20, which is keyed thereto by means generally indicated at 21. Rotor body 20 carries an L-shaped distributor finger 22 thereon, such finger having a radially disposed portion and a terminal portion 26 disposed at right angles thereto and parallel to the axis of shaft 15. Equally spaced angularly about the cap of the magneto unit, in position to cooperate with portion 26 of the distributor finger, is a plurality of high tension terminals 24 having points 25'. Eight such terminals are shown in the disclosed embodiment, since the magneto unit is designed to supply the ignition needs of an 8-cylinder engine. A central brush assembly, generally designated 27, supported axially of the cap con stantialy makes contact with distributor finger 22 thereby to distribute high tension current from coil 29 mounted within the magneto housing to the distributor finger.

it will be appreciated from the above that the generator of the magneto generates low tension electric current which is led, by wires not shown, to the low tension breaker assembly 17. The cam 16 which has 8 lobes, opens the contacts of the low tension breaker assembly at the required time, so that the low tension current fed to the primary of high tension coil 2& is interrupted. The resulting changes in the flux of the coil causes high tension impulses to be generated in the secondary of the coil. Such impulses are led through cable 32 to the entral brush assembly 27. At each such impulse, part 26 of the distributor finger 22 confronts the appropriate contact point 25 of a high tension terminal 24, so that the spark plugs (not shown) which are connected to such terminals discharge in sequence.

The means for attaching the cam 16 to shaft 15 in accurately oriented angular position thereon is shown more clearly in FIGS. 2 and 3. A blind hole is located radially of shaft 15 at the correct position longitudinally thereof. A resilient stiff split pin-like sleeve member 31, having a relaxed diameter somewhat greater than that of the hole 34), is pressed into such hole with the slot 32 in the sleeve facing axially outwardly of the shaft toward the cap of the distributor. Both ends of the sleeve are beveled at 34, to aid in insertion of the sleeve regardless of which end is placed in hole 3%. Cam 16 has a sleeve portion 35 of reduced diameter at one end thereof, such sleeve portion having an axially extending slot 36 therein adapted resiliently to receive the outer end of sleeve 31 after the latter has been inserted in hole 30.

The radially inner ends of the sides of the split sleeve 31 constantly resiliently engage the walls of hole 30 in shaft 15, and the radially outer ends of the sides of the split sleeve constantly resiliently engage the sides of slot 36 in portion 35 of cam 16. As a result, the cam is securely held on the shaft against rotation with respect to the shaft and also against fortuitous movement axially of the shaft. The cam may, however, be easily assembled on theshaft or disassembled from it by atool engaging the cam and thrusting it in the proper direction axially of the shaft.

In a typical satisfactory distributor made in accordance with the present invention, hole 30 in shaft 15 has a diameter of .125, +002, -.000 inches, slot as has a Width equal to such diameter, and split sleeve 31, which is made of carbon steel SAE. 1095, has a relaxed diameter of .135 inch.

Although only one embodiment of the attaching means of the invention has been illustrated in the accompanying drawings and described in the foregoing specification, it is to be especially understood that various changes, such as in the relative dimensions of the parts, materials used, and the like, as well as the suggested manner of use of the apparatus of the invention, may he made therein without departing from the spirit and scope of the invention as will now be apparent to those skilled in the art.

What is claimed is:

1. In a device having a rotatable shaft and a sleevelike member mounted on the shaft so as to rotate therewith, the improved means for securing" the member on the shaft in the desired angular position which comprises a passage in the shaft generally radially thereof, a slot in the wall of the member aligned with the passage, said slot being of generally the same width as the diameter of the passage and extending longitudinally from one end of the member, and a stiff resilient tubular pin positioned in the passage and extending into the slot, said pin having a slot through the wall thereof disposed generally 1ongitudinally of the pin and lying generally in an axial plane through the shaft, the tubular pin having a relaxed diameter somewhat exceeding the diameter of the passage and the first-named slot and forcibly engaging the walls of the passage and the first-named slot.

2. In a distributor for an internal combustion engine, said distributor having a housing, a shaft journalled in the housing of the distributor and adapted to be driven in synchronism with the engine, a cam mounted on the shaft and having at least one lobe on the periphery thereof, and a set of breaker points operated by the cam, the improved means for securing the cam on the shaft in the desired angular position which comprises a cylindrical passage in the shaft generally radially thereof, an open ended axially extending slot in the inner end of the cam of generally the same width as the diameter of the passage, and a stiff resilient tubular pin positioned in the passage and extending into the slot, said pin having a slot through the wall thereof disposed longitudinally of the pin lying generally in an axial plane through the shaft, and facing the outer end of the cam, the tubular pin having a relaxed diameter somewhat exceeding the diameter of the passage and the first-named slot and f0rci bly engaging the walls of the passage and the first-named slot.

References Cited in the file of this patent UNITED STATES PATENTS 1,641,370 Berkdoll Sept. 6, 1927 1,792,072 Chryst Feb. 10, 1931 2,648,247 Schrnuziger Aug. 11, 1953 2,808,996 Delfox Oct. 8, 1957 2,941,049 Begian lune 14, 1960 FOREIGN PATENTS 659,939 Germany May 17, 1938 

